The present invention relates to devices and methods for cleaning tire molds, particularly to methods and apparatuses for cleaning tire molds using a laser mounted onto a robot control apparatus.
Presently, two-piece tire molds and segmented tire molds are typically cleaned in semi-automatic machines which use metal shot, plastic beads, or glass beads as the cleaning or blasting agent. All of these blasting agents are abrasive and cause rapid wear to tire mold lettering and sidewall designs.
Another problem encountered by the past cleaning machines was recovery of the blasting agent, such as the sand or glass beads. After the blasting agent had been used to clean a tire mold, it had to be recovered or removed. The recovery of the blasting agent increased the time necessary to clean tire molds and caused a housekeeping problem in the plant.
One such abrasive tire blasting apparatus is found in U.S. Pat. No. 3,905,155 to Smith et al., which discloses a machine that provides a removable hood for positioning over a tire mold and a mechanism to blast the tire mold with abrasive glass beads.
Additionally, as disclosed in international Application Serial No. PCT/US96/13521, filed on Aug. 22, 1996 and having a common assignee with the present invention, a solid CO2 blasting media, which is not abrasive, is used to clean two piece and segmented tire molds. While the process has proved to be successful, there is a high noise level generated in carrying out the process.
Other than blasting, the prior art teaches using concentrated heating sources to loosen material for easier removal from a mold. An example is presented in the British Patent No. GB 269,721 to Stephenson, et al, which discloses a multi-jet arrangement for oxyacetylene blowpipe flames. As seen in their FIG. 1 and FIG. 2, the blowpipes are disposed along the cross section of the mold xe2x80x9cso that a much larger area can be treated simultaneouslyxe2x80x9d as the mold is rotated past the blowpipes. Thus, as the mold is rotated, each blowpipe traverses a different annular portion of the mold surface. The apparatus includes subsequent brushing with metal wire brushes to assist in removing the material loosened by the heating flames.
Recently, laser systems have been used for cleaning surfaces. The laser radiation can produce surface heating which is sufficiently rapid and intense to xe2x80x9cblast awayxe2x80x9d surface contamination without the need for any physical contact means such as brushing. For example, U.S. Pat. No. 5,373,140 to Nagy discloses a system for cleaning molds within presses including a light source such as a laser to clean surfaces within the mold. The light source may be formed as a portable unit moving between different presses or may be in the form of a single laser with a plurality of light paths leading from the laser to individual presses to clean the molds within the presses.
The Nagy patent uses the term xe2x80x9clightxe2x80x9d to refer generically to the radiation emitted from a laser. In keeping with this practice, the terms xe2x80x9cradiationxe2x80x9d and xe2x80x9clightxe2x80x9d will be considered interchangeable in reference to laser emissions throughout the present patent document.
Another method for cleaning molds with a laser is disclosed in German Patent No. DE 195 17 218, which states, for example, a process and apparatus comprises a conventional portable laser device with a working head which is driven on the heating press to be cleaned via a pivoting manipulator, or hinge-jointed beam arm, provided with mirrors for transmitting laser pulses to the laser working head. The laser working head can be under computer control, and a suction system used to collect the laser-removed dirt.
A device for contactless removal of a film from a structural part and for cleaning a surface by means of a pulsed laser beam, disclosed in German Patent No. DE 44 13 218, comprises a TEA-CO2 laser as the laser radiation source where the laser beam is guided by reflecting and focusing optic devices through a flexible opto-mechanical hinge-jointed arm which is hinge jointed to the working head and to the laser radiation source. An adaptive optical system in the arm or working head can include curved mirrors and/or a lens.
Another method for cleaning a surface with a laser, as disclosed in U.S. Pat. No. 5,151,134, states for example xe2x80x9can optical system is provided to separate the laser beam into a plurality of individual laser beams with energies approximately equal to each other and guided by an optical fiber assembly together with a recombining of the individual beams into a single laser beam.xe2x80x9d The recombined output beam is generally circular with a diameter controlled by an afocal optical assembly. Yet another apparatus for cleaning surfaces with a laser is disclosed in U.S. Pat. No. 5,531,857 to Englesburg et al wherein, for example, xe2x80x9cGas is flowed across the substrate treatment surface and the substrate is continuously irradiated . . . to release surface contaminants from the substrate treatment surface . . . .xe2x80x9d
Applicants recognized a need for a method and apparatus for cleaning tire molds with a laser that was quick, efficient, and less noisy than the prior art methods and achieve.
The present invention contemplates a new and improved tire mold cleaning method and apparatus which is simple in design, effective in use, and overcomes the foregoing difficulties and others while providing better and more advantageous overall results.
It is an object of the present invention to provide a robotic laser tire mold cleaning system (device) and method of operating the system, the system as defined in one or more of the appended claims and, as such, having the capability of being constructed to accomplish one or more of the following subsidiary objects.
It is another object of the present invention to provide a new and improved robotic laser tire mold cleaning system and method of use for cleaning a mold, particularly a tire mold.
It is yet another object of the present invention to provide a new and improved robotic laser tire mold cleaning system and method of use for cleaning a mold which uses a laser mounted on a robot to clean a tire mold.
It is still another object of the present invention to provide a new and improved robotic laser there mold cleaning system and method of use for cleaning a mold which uses a robot mounted laser to clean a tire mold while the latter mold is being rotated.
According to a first aspect, the present invention is a cleaning device for removing residual material from a mold having a molding surface. The device comprises a robot including an arm movable in a plurality of degrees of freedom, the arm having a free end. A laser is connected with the robot and has an output end mounted to the arm proximal to the free end so as to be positionable by the robot. The robot positions the output end of the laser with respect to the molding surface to direct light from the laser to impinge on the surface and remove residual material from the surface.
According to another aspect, the present invention is a method of cleaning residual material from the molding surface of a mold comprising the following steps: providing a robot having an arm movable in a plurality of degrees of freedom and a laser connected with the robot and having an output end mounted to the arm; automatically moving the arm to align the output end of the laser with the molding surface; and activating the laser such that laser light impinges on the molding surface and removes residual material disposed on the surface.
In yet another aspect, the present invention is a system for cleaning a metallic object. The system comprises a robot including an arm movable in a plurality of degrees of freedom, the arm having a free end. A laser is connected with the robot and has an output end mounted to the arm proximal to the free end so as to be positionable by the robot. A rotatable support is disposed proximal to the robot and is configured to support the object and rotate the object with respect to the output end of the laser.
One advantage of the present invention is that the cleaning apparatus is completely automatic.
Another advantage of the present invention is that the beam of laser light is non-abrasive and does not damage the tire mold.
Another advantage of the present invention is that the laser light provides single pass cleaning of the tire mold as opposed to multiple passes required by existing systems.
Another advantage of the present invention is that the laser light also cleans the tire molds without generating a loud noise level.
Still other benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification.